<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>v-cloak解决闪屏</title>
</head>
<body>
<style>
  [v-cloak] {
    display: none;
  }
</style>

<div id="app" v-cloak>
  <p>{{msg}}</p>
</div>

<script src="https://cdn.jsdelivr.net/npm/vue@2.5.21/dist/vue.min.js"></script>
<script>
  <!-- 案例 -->
  let vm = new Vue({
            el: "#app",
            data: {
              msg: "123"
            }
          })
</script>
</body>
</html>